Loud-speaker



March 4, 1930. F. J. REICHMANN LOUD SPEAKER Filed May 6, 1926 Z1 2W1 /1 1. Fran/z J. Raf/2 //1 (01/1,

Patented ar. 4 13d w i a, Kg ten.

FRANK El. REICHMANN,

LQUEJFSEPFZAIKER Application filed May 6, 192%. Serial No. 10?,046.

This invention relates to sound reproducing devices, and more particularly to a re producing device of the so-called cone type, wherein a tympanum of comparatively large area is employed.

Reproducers, in general, are divided into several types, but tall principally in the horn type and the cone type. The latter is conceded to effect more etlicient reproduction over a wide range of voice frequencies than the horn type, but it possesses an undesirable tone characteristic which the horn within its most eflicient range does not have.

For this reason many people have continued 15 to use the horn type of speaker in radio reception in spite of the tact that the horn. can

be designed to reproduce faith-fully only within a comparatively narrow held.

The object of the present invention is the provision of a cone-type sound reproducer which in large measure will be free from the undesirable tonal characteristics of the cone and which will faithfully reproduce sounds having widely divergent frequencies.

A reproducer embodying the main features of the present invention is provided with a tympanumof large area comprising a flat annular portion and a cone portion, which cone portion may be integral or adhesively secured to the interior edge of the annular portion. The size of the tympanurn and the rel ative dimensions of the two portions thereof are arranged in accordance with certain characteristics which will he explained mord in detail hereinafter.

A sound reproducing device is operably mounted with respect to the cone speaker and has its tone arm adjustably secured to the apex thereof. 1 Other objects and features of the invention will be apparent from a consideration of the following detailed description, taken in connection with the accompanying drawings, in

Figure 1 is a front elevational view .of an instrument embodying the main features of the invention, part of the front grill being broken away to illustrate some or" the internal structural details;

Figure 2 is a rear elevational view of the same speaker;

Figure 3 is a sectional view taken on the line 3-3 of Figure 1, looking in the direction of the arrows; and

Figure 4 is a fragmentary elevation of portion of the margin of one type of cone.

Referring now to the single sheet of draw ing made a part of this specification and in which identical parts in the several views are designated by the same reference characters, the speaker comprises a tympanum generally designated by the reference character 10, said tympanum comprising a flat, annular portion 10 and a cone portion 10 The tympanum 10 may have an added rim portion 10 which may comprise an annular metallic member, or a similar member of other material, It may also be produced by building up the rim with materials applied thereto. its purpose is to reinforce the margin of the tympanum and to stretch the material thereof. By stretching the material thereof and by adding to its mass, it regulates and controls the pitch of the tympa num 10.

Any suitable means may be employed for attaching the ring 10 where made separately from the tympanum 10. Synthetic processes of a number of types may be employed to build up the rim material. lit is also possihie that the reinforcement may be formed as an integral part of the material or? the tympanum 3.0.

as a specific example of the manner in which the reinforcement on the exterior portion of the rim may he obtained 1 have found that ll get uniformly good results by the use of any one of the following procedures. A. single sheet of paper out to form a ring may he adhesively secured to one side oi; the. eriphery of the rim portion. $ubstantia ly the same procedure can be resorted to endure interning section of paper in ring form securedto both sides or" the ring portion.

Instead of ordinary mucilage l have employed a varnish ot phenolic condensation product, H1 its intermediate stage and subsequently reduced it to its final stage by heat and pressure to obtain substantially homogenous final structure. An alternative use of phenolic condensation product is to simply coat the periphery ofthe rim portion with mated need not be fibre in its character at all. It may be a molding'compound employing. the usual gums such as kauri, copal, damar or such materials as rubber, gutta percha,

balata, or combinations of these. When using the latter type of material the impregnation of the edge of the rim with latex thereon and subsequently vulcanizing the solid constituent of the latex can be. resorted to.

As a still further example, sheets of metal 20 may be secured to the edge of the rim either by clamping or by the employment of any other suitable means, including gluing, whereby the reinforcement can be kept in place.

25 In addition to the rim structure just described, which is optional in the structure now to be set forth, the invention relates particularl to the shape and size of the tympanum. bviousl y some supporting strucao ture is necessary, and in the present instance I have designed a supporting structure which is novel in design and of particular utility in mounting a tympanum of the type disclosed, and which is also a part of the subject matter of this invention.

A cylinder or hoop-like ring 11 is secured to a base 12 by' any suitable means. The base 12 comprises a composition of .material adapted to be molded when plastic, which forms the outer portion of the base and is designated 12. Within the molded portion 12 is ablock of wood or other suitable material 12. Through this wooden base 12 are screw holes through which screws 13 ass to secure the frame 11 to the base 12. elt may be used to cover the bottoms of base portions 12 and 12, the latter being undercut to provide room for heads of screws 13, which pass upwardly through block 12".

A plurality of grooves 14.15 are arranged about the inner surface of said hoop-like member 11 at equal distances apart to form parallel tracks or seats. The cone 10 is disposed within the hoop-like member 11 and 1s compensatin 'ly secured between a pair of annular inem bers'lfi and 17 seated in said tracks 14 and 15.

Felt rings 19 and..20 preferably adhesively secured to members 16 and 17 are placed beid tween the annular members 16 and 17 and the portion 10 or 10 of the cone. Other material than felt may be used for the cushion rings 19 and 20 and these may be secured other than by an adhesive. In this we it u will be seen that the cone 10 is secure in the frame between pads or cushions whereby a sufficiently secure construction is obtained but a r1 id fastening for said cone 10 is avoided. T e cone 10 is adapted to slide or slip about between the felt rings 19 and 20 permitting compensation for jarring and strains during shipping and improvin the character of its sound reproduction. here is no opportunity for the cone to rattle or make mechanical noises. I

In order to afford a moun ing for the telehone unit which is referred to generally y the reference character 25, a grille construction is employed, said grille consisting of a single U-shaped member 26 having diverging arms 27, said arms 27 bein riveted or otherwise secured at their en s which have upturned flange portions 28 to the frame 11. Screws may be employed for attaching the grille 26. A transverse bar.28' having flanged ends' 28 may be used to secure to said upright members the tele hone unit to the grille 26, screws or rivets ing adapted to pass through the member 26 and said flanges.

Said telephone unit 25 may be of any usual design, but it is arranged so that the armature or moving element thereof can be secured to the cone 10 at its apex in order to impart vibrations thereto. To illustrate one mode of making said connection, Figure 3 shows a connecting rod 30 secured to the apex of the cone by means of an adjusting nut 31. The usual small metal cones 32 and 33 are employed to reinforce the apex of the cone 10 and afford a better connection for the connecting rod 30, while any suitable means such as a cone shaped nut 34 may be provided on the inner portion ofsaid connecting rod 30 whereb said cone may be clamped in order to a 0rd a tight engagement thereof.

In the means which is employed for supporting the members 16 and 17 in clamping relationship, it is unnecessary to insert fastenin means through vthe tympanum 10. This 1s a decided advantage both in structure and in reproduction. I have shown in the drawings the structure which I prefer to use in order to accomplish this result. It will be noticed that the rings 16 and 17, which I have described, are slip rings.

When rings having overlapping ends are desired, a pair of annular interior indentures such as are shown in Figure 3 are rovided in the hoop-like ring 11. The mem ers 16 and 17 when made with overlapping ends may be so arranged that one has a plain aperture therein and the other a threaded a erture. B expanding) the members 16 and 1 made as last descri ed and securing the ends together by means of screws, these members may be securely retained in the hoop-like ring 11. When desired the annular tracks 14 and 15 may be omitted and the expansion of the as es rings 16 and 17 may be used to secure retention without the necessity of employing any other fastening means.

A handle 37,.may be provided at the upper- .most portion of the instrument and may be ure 2 in order to exclude it from view when facing the front of the instrument. In order to present a pleasing appearance, as well as to perm1t the sound totravel readily in both directions, I place a grille 40 over the face of the cone, said grille 40 preferably being confined within the hoop-like member 11 and secured to thefastening members 15 by machine screws 41-41.

The relative size of the diflerent portions of the tympanum has a very greateifect upon the results obtained therewith. I have found that a cone having a diameter of not less than six-tenths of the overall diameter of the tympanum, nor more than eight-tenths thereof, when used in accordance with the present invention, ives very good tonal results. The altitude o one-third the diameter.

To illustrate, in my preferred form of tympanum, the entire overall diameter of the portion 10, which is held between the clampin members 16 and 17, is approximately thirteen and one-quarter inches, the diameter of the cone about eight and three-quarter inches, and the height thereof about three and onehalf inches. Numerous experiments seem to show that these approximate dimensions are the best, but I find that I can obtain fairly good results if the diameter of the cone is not nore than eight-tenths, nor less than six-tenths of the overall diameter of the tympanum, and if the altitude of the cone is not less than one-third the diameter of the base.

The material of the cone, as intimated ina I prior paragraph, may vary, depending upon the particular characteristics desired. nor

example, the material employed in the cone portion and annular port1on may difier, or the same material may be employed and the thickness thereof vary. Of course the material for both parts may be exactly the same. With the mounting which I have shown and the preferred shape and size of the tympanum, I have found that I obtain the best results b using a thin varnished good rag paper, relhtively light in weight, but possessing considerable mechanical strength. a

v The tympanum' may be formed n a single piece from pulpous material, or it may he formed from sheet material, cut into the proper figure and adhesively secured to a the structure pictured. I prefert his latter type of construction because athinner and stronger cone can be produced sinpe the cone portion may be secured to the annular portion so firmly as to result practically no a single the cone should also be at least produce unitary structure. Moreover, this structure is apt to be much more economical and from the point of view of a manufacturer it is to be preferred for this reason as well.

In the foregoing description I have laid particular stress upon the size and shape of the tympanum which I employ and have described in detail the means for holding it in operable relation to a telephone unit. Although particularly gobd resultsare obtained by a combination such as this, it is obvious that some of these features may be employed independent of the others. For instance, I could employ difierent mounting for the tympanum and still obtain goods results, while the structural details of the mounting would have great utility independent of the type of cone employed. I do not wish, therefore, to be bound by the particular description of these features, but I wish the invention to be limited only as defined by the scope of the appended claims.

The sliding of the tympanum within the frame saves tremendous losses in shipping.

rim of the tympanum in the frame or in adjusted relation to the unit to obtain good reception. A ireedom of movement is necessary to compensate for ars and strains 111- cident to handling.

An added advantage of the ring construction here described is rapidity of assembly,

coupledwith the probability of no connection therewith.

I claim:

i 1. ln a cone type sound reproducer, a composite tympanum having a fiat, annular portion, and a central conical portion,-annular non-vibrating members secured in compeneating relationship to the periphery of said annular portion, and means for'imparting vi bration to said composite tympanum, and in which said non-vibrating members comprise a pair of annular metal members having a facing of felt disposed adjacent said tympanum.

2. in a cone type sound reproducer, a composite tympanum having a flat, annular portion, and a central conical portion, annular non-vibrating members secured in compeneating relationship to the periphery of said annular portion, and means for imparting vibration to said composite tympanum, and in which said conical section is secured at its base to the interior edge of the annular portion and in which a telephone unit is provided error in with actuating rod, said rod being adjust three-quarters inches in diameter and an altitude of about three and one-half inches, and

combined with said tympanum a sound reprobers secured in said indentures and holding said tympanum therebetween, and means for causing a vibration of said tympanum.

6. A sound reproducer as defined in claim 5, in which a brace is secured to the interior portion of said hoop-like member and in which the means for imparting vibration to said tympanum comprises a telephone unit secured to said brace member. 3

7. A reprod'ucer as defined in claim 5, in

tion to said frame, and an external shel upon said body and adapted to be applied thereto while in a plastic condition, said shell being adapted to reduce vibration in said body portion.

FRANK J. REIOHMANN.

which said tympanum comprises a flat, annular portion secured between said clamping members, and a central conical section secured thereto.

8. A sound reproducer as defined in claim 5, in which said tympanum comprises a fiat, annular portion, and a conical portion, the altitude of said cone being at least one-third of the diameter of the base thereof.

9. A re roducer as defined in claim 5, in which sai tympanum comprises a flat, annular portion,-and a conical portion, in which said conical portion is not less than six-tenths the entire available diameter of the tympanum.

10. A reproducer as defined in claim 5, comprising a flat, annular portion and central conical portion, the cone portion being not more than eight-tenths the entire available diameter of said tympanum.

' 11. A reproducer as defined in claim 5, in which said tympanum comprises a flat, annular portion and a central conical portion, in

which the diameter of said conical portion is not more than eight-tenths the entire available diameter of said tympanum, and in which the altitude of said cone is at least onethird the diameter of the base thereof."

12. In a cone type speaker, a frame having tracks, rings disposed in said tracks, and a tympanum movably disposed intermediate said rings.

13. In a cone type speaker, a frame having a track forming portion, guide members in said portion, a tympanum disposed between said guide members, and a cushion intermediate said guide members and said tympanum.

14. In a cone type speaker, a frame having tracks, ring members frictionally held in said tracks, and a tympanum 'slidably disposed intermediate said rings.

15. In a loud speaker of the cone type, a 

